Microtome Having Means for Reversing a Direction of Rotation

Abstract

The present invention relates to a microtome ( 10 ) including a first shaft ( 12 ) which is arranged in a fixed position and capable of being driven by a handwheel and which has a first gear wheel ( 14 ) non-rotatably mounted thereon. The microtome ( 10 ) further includes a second shaft ( 16 ) which is arranged in a fixed position and has a second gear wheel ( 18 ) non-rotatably mounted thereon. The first gear wheel ( 14 ) and the second gear wheel ( 18 ) are coupled to each other via a transmission unit ( 20 ), so that the second shaft ( 16 ) can be driven by the first shaft ( 12 ). In a first position of the transmission unit ( 20 ), the two shafts ( 12, 16 ) are rotatable in the same direction, while in a second transmission position, they are rotatable in opposite directions.

What is claimed is: 
     
         1 . A microtome comprising:
 a first shaft ( 12 ) which is arranged in a fixed position and capable of being driven by a handwheel;   a first gear wheel ( 14 ) non-rotatably mounted on the first shaft;   a second shaft ( 16 ) arranged in another fixed position;   a second gear wheel ( 18 ) non-rotatably mounted on the second shaft; and   a transmission unit ( 20 ) via which the first gear wheel ( 14 ) and the second gear wheel ( 18 ) are coupled to each other so that the second shaft ( 16 ) can be driven by the first shaft ( 12 );   wherein the first shaft ( 12 ) and the second shaft ( 16 ) are rotatable in the same direction when the transmission unit ( 20 ) is in a first position; and   wherein the first shaft ( 12 ) and the second shaft ( 16 ) are rotatable in opposite directions when the transmission unit ( 20 ) is in a second position.   
     
     
         2 . The microtome ( 10 ) as recited in  claim 1 , wherein when the transmission unit is in the first position, the first gear wheel ( 14 ) and the second gear wheel ( 18 ) are coupled to each other by an odd number of idler gears ( 22  through  26 );
 wherein when the transmission unit is in the second transmission position, the first gear wheel ( 14 ) and the second gear wheel ( 18 ) are coupled by an even number of idler gears ( 22  through  26 ). 
 
     
     
         3 . The microtome ( 10 ) as recited in  claim 1 , wherein when the transmission unit is in the first position, the first gear wheel ( 14 ) is coupled to the second gear wheel ( 18 ) by a first idler gear ( 22 ), the first gear wheel ( 14 ) being in meshing engagement with the first idler gear ( 22 ), and the first idler gear ( 22 ) being in meshing engagement with the second gear wheel ( 18 );
 wherein when the transmission unit is in the second position, the first gear wheel ( 14 ) is coupled to the second gear wheel ( 18 ) by a second idler gear ( 24 ) and a third idler gear ( 26 ), the first gear wheel ( 14 ) being in meshing engagement with the second idler gear ( 24 ), the second idler gear ( 24 ) being in meshing engagement with the third idler gear ( 26 ), and the third idler gear ( 26 ) being in meshing engagement with the second gear wheel ( 18 ).   
     
     
         4 . The microtome ( 10 ) as recited in  claim 3 , wherein the first idler gear ( 22 ) has a greater diameter than the second idler gear ( 24 ) and the third idler gear ( 26 ). 
     
     
         5 . The microtome ( 10 ) as recited in  claim 3 , wherein the second idler gear ( 24 ) and the third idler gear ( 26 ) are arranged at an angle to the first idler gear ( 22 ) and/or to the first and second gear wheels ( 14 ,  18 ). 
     
     
         6 . The microtome ( 10 ) as recited in  claim 2 , wherein the idler gears ( 22  through  26 ) are arranged in a fixed position relative to each other on a bearing unit ( 28 ); and
 wherein the bearing unit ( 28 ) is movable relative to the first gear wheel ( 14 ) and the second gear wheel ( 18 ). 
 
     
     
         7 . The microtome ( 10 ) as recited in  claim 1 , wherein the transmission unit ( 20 ) can be shifted manually between its first and second positions by means of a shifting unit ( 34 ). 
     
     
         8 . The microtome ( 10 ) as recited in  claim 7 , wherein the microtome ( 10 ) includes a housing;
 wherein the shifting unit ( 34 ) includes a manually operable actuating element, at least a portion of which is located outside of the housing.   
     
     
         9 . The microtome ( 10 ) as recited in  claim 7 , wherein the shifting unit ( 34 ) includes an eccentric ( 36 ) for translationally shifting the transmission unit ( 20 ). 
     
     
         10 . The microtome ( 10 ) as recited in  claim 1 , wherein the transmission unit ( 20 ) is retained in the first position by a resilient element ( 38 ), in particular a compression spring; and
 wherein the transmission unit ( 20 ) is movable from its first position to its second position against a restoring force of the resilient element ( 38 ).   
     
     
         11 . The microtome ( 10 ) as recited in  claim 1 , wherein the microtome ( 10 ) is a rotary microtome.